The present invention relates to a printing unit with a printing cylinder having simplified removal and locking. More particularly, the invention relates to a flexographic printing unit with a printing cylinder which can be easily removed from its seat and can be locked simply.
It is known that printing units, for example for flexographic printing, are provided with a plurality of printing cylinders: a first cylinder is an inking cylinder which dips into an ink tray in order to draw ink for printing; a second cylinder is a cylinder on which the print to be transferred to paper or another medium is provided; and a third cylinder is the actual printing cylinder, against which the cylinder that bears the type abuts in order to perform printing on the paper that winds around the printing cylinder.
Finally, a fourth cylinder arranged downstream of the printing cylinder allows to transport the printed paper from one printing unit to a subsequent printing unit or to the outlet at the end of the printing cycle.
The printing cylinder requires frequent operations for replacing it, in order to pass from one diameter to another, depending of the type of printing to be performed.
Replacing the printing cylinder usually takes time, since it is necessary to release the cylinder from its seat and then remove it. These operations are difficult owing to the configuration of the printing unit, and this difficulty, when it is necessary to replace several printing cylinders, entails long replacement times, for example in the case of a plurality of printing units arranged in series.
Moreover, the printing cylinder must be adjusted in its position with respect to the cylinder bearing the type, which accordingly abuts against the printing cylinder.
The aim of the present invention is to provide a printing unit with a printing cylinder which can be easily removed and just as easily locked in its seat.
Within the scope of this aim, an object of the present invention is to provide a printing unit with a printing cylinder which can be released, and then removed, with a single simple operation without having to disassemble fixed parts of the printing unit.
Another object of the present invention is to provide a printing unit with a printing cylinder whose position can be adjusted with respect to the cylinder that bears the type and with respect to an impression cylinder.
Another object of the present invention is to provide a printing unit with a printing cylinder which can be adjusted vertically and horizontally with respect to the cylinder that bears the type.
Another object of the present invention is to provide a printing unit having a printing cylinder which can be removed easily, is highly reliable, relatively easy to manufacture and at competitive costs.
This aim, these objects and others which will become apparent hereinafter are achieved by a printing unit with removable printing cylinder, characterized in that it comprises two outer shoulders which are adapted to constitute a supporting frame for a printing cylinder, a first pair of arms and a second pair of arms which are pivoted at an upper end of each one of said shoulders and form a seat for accommodating said printing cylinder, means for locking said printing cylinder being provided in order to retain said printing cylinder so that it rests on said first and second pairs of arms. dr
Further characteristics and advantages of the invention will become apparent from the description of a preferred embodiment thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein:
FIG. 1 is a partial perspective view of the means for adjusting and locking the printing cylinder, with the printing cylinder removed;
FIG. 2 is a partial side view, with the printing cylinder shown in the removed position;
FIG. 3 is a partial side view of the printing cylinder accommodated in its seat and locked thereat;
FIG. 4 is a top plan view of the seat for accommodating the printing cylinder and the corresponding locking means;
FIG. 5 is a plan view, similar to FIG. 4 but with the printing cylinder arranged in the appropriately provided seat; and
FIG. 6 is a partially sectional front elevation view of the arrangement of the printing cylinder in the appropriately provided seat and of its corresponding locking.